Effects of Harvest and Climate Change on Polar Marine Ecosystems
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Effects of Harvest and Climate Change on Polar Marine Ecosystems Case Studies from the Antarctic Peninsula and Hudson Bay by Carie Hoover B.Sc., The University of California Santa Barbara, 2002 M.Res., The University of St Andrews, 2005 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in The Faculty of Graduate Studies (Resource Management and Environmental Studies) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) April 2012 ⃝c Carie Hoover 2012 Abstract This thesis applies food web modelling to increase our understanding of how the interaction of climate change and exploitation have historically altered, and continue to alter, marine polar ecosystems. Understanding stressors responsible for ecosystem level changes is important not only to the people and industries reliant on the resources, but for managers to make future decisions on resource uses. The first two chapters develop models of Hud- son Bay (Arctic) and Antarctic Peninsula (Antarctic) marine ecosystems, focused on re-creating changes in the past 30 years. Both ecosystems have undergone changes due to environmental factors, which are incorporated into the models. While the Hudson Bay model exhibits a shift from benthic to pelagic species, the Antarctic Peninsula model is identified to have more uniform declines across all species, as the main trophic link in the ecosystem, Antarctic krill declines. Model simulations are continued in the next two chapters, whereby future environmental changes are tested in conjunction with multiple exploitation levels. For Hudson Bay, continued harvest of ma- rine mammals at current conditions results in large-scale declines for some species (narwhal, eastern Hudson Bay beluga, polar bears, and walrus), in- dicating current harvest levels are too high to sustain long term. Further shifts from benthic to pelagic species in the lower trophic levels favor fish species such as capelin and sandlance. Future simulations of the Antarctic Peninsula identify large reductions in ecosystem biomass of all species due changes in environmental conditions and an overall reduction in krill, with minimal ecosystem impacts from harvest. In the last chapter, an economic model is constructed to assess the use value of hunting narwhal and bel- uga in the Hudson Bay region. The economic impact to northern residents is considered as future model simulations of Hudson Bay reveal that these species may be susceptible to population declines, and issues of food security are becoming increasingly important. Economic analysis reveals the moti- vation to hunt in Hudson Bay may not be economically-driven, there are substantial benefits derived by northern communities through narwhal and beluga hunts. Results for each ecosystem are discussed as they pertain to future research and management of each ecosystem. ii Preface A version of chapter 2, co-authored with Tony Pitcher and Villy Christensen, has been re-submitted with revisions to Ecological Modelling. I constructed the model and wrote the manuscript. Villy Christensen was key in the de- velopment of the model structure, fitting of the model, and other technical model aspects. Tony Pitcher provided guidance on model construction and discussions on the direction of the manuscript. A version of chapter 4, co-authored with Tony Pitcher and Villy Christensen, has been re-submitted with revisions to Ecological Modelling. I created the model simulations and wrote the manuscript. In addition to their assistance with chapter 2 which utilizes the same model, both Villy Christensen and Tony Pitcher provided guidance with the future simulations. Villy Chris- tensen also provided technical model assistance. A version of chapter 6, co-authored with Megan Bailey, Jeff Higdon, Steve Ferguson, and Rashid Sumaila, has been re-submitted with revisions to the journal Arctic. I conceptualized and constructed the model in addition to writing the manuscript. Megan Bailey assisted in model construction. Rashid Sumaila and Megan Bailey provided the framework for the model and assistance on economic analyses. Jeff Higdon and Steve Ferguson pro- vided expertise on model parameters, in addition to Jeff Higdon collecting input parameter values during fieldwork in the north. All authors provided feedback on the submitted manuscript. Chapters 3 and 5 are co-authored with Tony Pitcher and Evgeny Pakhomov, and will be submitted to a peer-review journal. I constructed the model for chapter 3, created the model simulations for chapter 5, and wrote both manuscripts. Tony Pitcher provided the idea for the model and guidance throughout the model construction, and provided guidance with model sim- ulations. Evgeny Pakhomov was key in providing expertise to the ecology of the model which was important to the fitting process, and contributed to the ecological relevance of the model. iii Table of Contents Abstract ................................. ii Preface .................................. iii Table of Contents ............................ iv List of Tables .............................. vii List of Figures .............................. ix Acknowledgements ........................... xii Dedication ................................ xiv 1 Introduction ............................. 1 1.1 Ecosystem-Based Management . 1 1.2 Study Areas . 3 1.3 Ecopath with Ecosim . 10 1.4 Thesis Outline . 11 2 Impacts of Hunting, Fishing, and Climate Change to the Hudson Bay Marine Ecosystem 1970-2009 .......... 15 2.1 Synopsis . 15 2.2 Introduction . 16 2.3 Methods . 18 2.4 Results . 27 2.5 Discussion . 41 3 Effects of Harvest and Climate Change on the Antarctic Peninsula Marine Ecosystem (FAO area 48.1) ........ 47 3.1 Synopsis . 47 3.2 Introduction . 48 3.3 Methods . 51 iv Table of Contents 3.4 Results . 60 3.5 Discussion . 73 4 Future Impacts of Hunting, Fishing, and Climate Change on the Hudson Bay Marine Ecosystem ............ 80 4.1 Synopsis . 80 4.2 Introduction . 81 4.3 Methods . 84 4.4 Results . 91 4.5 Discussion . 109 4.6 Hudson Bay Biomass and Morality Figures . 116 5 Future Impacts of Fishing and Climate Change on the Antarc- tic Peninsula Marine Ecosystem ................ 121 5.1 Synopsis . 121 5.2 Introduction . 122 5.3 Methods . 124 5.4 Results . 130 5.5 Discussion . 158 5.6 Antarctic Peninsula Biomass and Mortality Figures . 165 6 Estimating the Economic Value of Narwhal and Beluga Hunts in Hudson Bay, Nunavut ..................... 172 6.1 Synopsis . 172 6.2 Introduction . 173 6.3 Methods . 176 6.4 Results . 196 6.5 Discussion . 202 7 Conclusions ............................. 209 7.1 Chapter 1 . 209 7.2 Hudson Bay . 209 7.3 Antarctic Peninsula . 213 Bibliography ............................... 217 Appendices A Hudson Bay Ecosystem Model Parameters and Details .. 287 A.1 Model Parameters by Functional Group . 287 v Table of Contents A.2 Fisheries Input . 325 A.3 Model Fitting Parameters and Data Sets . 333 A.4 Model Parameterization and Output . 336 B Marine Mammal Mortality Equations ............. 346 C Hudson Bay Bird Species ..................... 348 D Hudson Bay Fish Species ..................... 353 E Hudson Bay Model Vulnerabilities ............... 355 F Hudson Bay Mixed Trophic Impacts .............. 358 G Hudson Bay Monte Carlo CV Values ............. 367 H Hudson Bay Monte Carlo Results ............... 369 I Hudson Bay Ecosim Biomass Trends by Species ...... 373 J Antarctic Peninsula Ecosystem Model Parameters and De- tails .................................. 376 J.1 Model Parameters by Functional Group . 376 J.2 Ecosim Input Parameters . 426 J.3 Model Parameterization and Output . 437 K Antarctic Peninsula Model Vulnerabilities .......... 453 L Antarctic Peninsula Model Mixed Trophic Impact Values 458 M Antarctic Peninsula Monte Carlo CV Values ........ 466 N Antarctic Peninsula Monte Carlo Results .......... 468 O Antarctic Peninsula Monte Carlo Graphs .......... 471 P Antarctic Peninsula Model Biomass Trends By Species . 473 vi List of Tables 2.1 Harvest trends used in the Hudson Bay Ecosim model . 26 2.2 Balanced Ecopath model parameters . 29 2.3 Trophic level of the ecosystem (TLE) and catches (TLC )... 37 3.1 Time series data used for Antarctic Peninsula model fitting . 55 3.2 Balanced Ecopath model parameters for the Antarctic Penin- sula . 62 3.3 Antarctic Peninsula trophic level of the ecosystem TLE and catches TLC ............................ 70 4.1 Hudson Bay future climate and hunting scenarios . 86 4.2 Summary of harvest values and hunting/fishing mortalities used for the initial Hudson Bay Ecopath model and future hunting scenarios . 89 4.3 Trophic level of ecosystem (TLE) and catches(TLC ) for each future Hudson Bay simulation . 94 5.1 Catches and fishing mortalities for each Antarctic Peninsula future scenarios. 129 5.2 Antarctic Peninsula future harvest and climate scenario names.130 5.3 Trophic level of ecosystem (TLE) and catches(TLC ) for the Antarctic Peninsula future simulations . 133 6.1 Parameter inputs for Hudson Bay economic model equations 188 6.2 Statistics for hunting communities in Hudson Bay . 195 6.3 Economic value including cost sharing and opportunity cost . 200 6.4 Contribution of revenue to each community . 201 A.1 Hudson Bay Ecopath marine mammal input parameters . 289 A.2 Hudson Bay fishing mortality based on per capita consump- tion rates . 306 A.3 Calculated input parameters for Hudson Bay fish groups . 309 vii List of Tables A.4 Comparison of parameters for benthic functional groups from high latitude Ecopath models. 320 A.5 Arctic killer whale harvests . 326 A.6